Dear Friends
I have my 3D model displayed on the screen. How can I capture the top view , side view and front view of that model. I am completely ignorant about that. Please give me some suggestions.
I am using perspective projection. Any help would be highly appreciated. Thanks Sujan

Moreover I am using perspective projection. Tell me how can I achieve isometric view in perspective projection.

You don't. What you asked for is a contradiction, like asking for a round square, or a meter stick that's 10 centimeter's long.

You can look at a scene from any angle. But as long as you are using a perspective projection, it will not be "isometric", because isometricness is contradictory to perspective projection. To be isometric, you need to use an orthographic projection.

Well, I would say that your code that sets up a projection matrix should be part of your render loop, not some random function that picks a DC out of nothing and binds the context. And it should be putting the projection matrix in the GL_PROJECTION matrix, not whatever matrix happened to be the current one at the time.

It should be noted that an isometric "projection" (http://en.wikipedia.org/wiki/Isometric_projection) is not a projection at all; it's just a specific case of an orthographic projection. Specifically, when you view a scene from a certain angle through an orthographic projective transform. That is, it's not just about the projection; you also need to change the angle of view.